$$225 \times 1000 \times 4.184 = 941,400 J$$

$$q = 2.5 \times 0.372 \times (29.9 - 25.0) = 4.6 J$$

$$q = m \times C \times \Delta T$$

$$q = 10 \times 4.184 \times (80 - 20) = 2,510.4 J$$

Question 1

Which of the following best describes a crystalline solid?

Accepted Answer

Atoms or molecules are arranged in a well-ordered, repeating three-dimensional structure.

Question 2

A sample of matter is observed to have a definite volume but no definite shape. Which state of matter is this sample most likely in?

Accepted Answer

Liquid

Question 3

Which of the following is an example of a chemical property?

Accepted Answer

Flammability of gasoline

Question 4

Which separation technique would be most appropriate to separate a mixture of sand and water?

Accepted Answer

Filtration

Question 5

A student heats 10.0 g of ice at 0°C until it becomes water at 0°C. What type of change has occurred?

Accepted Answer

A physical change

Question 6

Which of the following best illustrates the law of conservation of mass?

Accepted Answer

When 7.7 g of sodium reacts with 11.9 g of chlorine, 19.6 g of sodium chloride is produced.

Question 7

Which of the following is a homogeneous mixture?

Accepted Answer

Sweetened tea

Question 8

Which of the following equations correctly converts Celsius to Kelvin?

Accepted Answer

$$K = 	ext{°C} + 273.15$$

Question 9

A 225 Calorie (Cal) candy bar contains how many joules of energy? (1 Cal = 1000 cal, 1 cal = 4.184 J)

Accepted Answer

$$225 	imes 1000 	imes 4.184 = 941,400 J$$

Question 10

Which of the following is an example of an exothermic reaction?

Accepted Answer

Combustion of gasoline in a car engine

Question 11

A 2.5 g sample of gallium is heated from 25.0°C to 29.9°C. If the specific heat capacity of gallium is 0.372 J/g°C, how much heat is absorbed?

Accepted Answer

$$q = 2.5 	imes 0.372 	imes (29.9 - 25.0) = 4.6 J$$

Question 12

Which of the following is a pure substance?

Accepted Answer

Helium gas

Question 13

Which of the following statements about energy is FALSE?

Accepted Answer

Energy can be created and destroyed.

Question 14

Which of the following is a chemical change?

Accepted Answer

Rusting of iron

Question 15

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture with variable composition from region to region

Question 16

Which of the following is the correct equation for calculating the amount of heat absorbed or released by a substance?

Accepted Answer

$$q = m 	imes C 	imes \Delta T$$

Question 17

Which of the following is NOT a physical property?

Accepted Answer

Toxicity

Question 18

A sample of water is heated from 20°C to 80°C. If the mass of water is 10 g and the specific heat capacity is 4.184 J/g°C, how much heat is required?

Accepted Answer

$$q = 10 	imes 4.184 	imes (80 - 20) = 2,510.4 J$$

Question 19

Which of the following best describes the difference between an element and a compound?

Accepted Answer

A compound is composed of two or more elements in fixed proportions, while an element cannot be broken down into simpler substances.

Chapter 3: Matter and Energy – Study Notes for Introductory Chemistry

Guida di studio - Domande di pratica